Thank you both, indeed combining two solutions fixed my problem : > which(sapply(mylist, mycompare,find)) [1] 2
I admit list of lists is not the optimal design, it's out of my control but is there is not much data in it, so performance is not an issue. For the sake of R's honour I didn't want to use "for loop". ce -----Original Message----- From: "Jeff Newmiller" [[email protected]] Date: 03/11/2017 11:23 AM To: [email protected], "ce" <[email protected]>, "Rui Barradas" <[email protected]> Subject: Re: [R] find index in a list of list Since the offered solution already checks each top level element using the "identical" function, you just need a different comparison function, like perhaps: mycompare <- function( x, y ) { identical( x[[ "a" ]], y[[ "a" ]] ) && identical( x[[ "b" ]], y[[ "b" ]] ) } Note that your decision to store this data in a list of lists is making this search process much less computationally and syntactically efficient than it would be if you could fit your data into a data frame. -- Sent from my phone. Please excuse my brevity. On March 11, 2017 7:17:11 AM PST, ce <[email protected]> wrote: > > >Sorry I rejoiced too soon. In fact original list is more complex like >: > >mylist <- >list(list(a=10,b="x",c=1),list(a=11,b="y",c=2),list(a=12,b="z",c=5)) > >and I still need to find index of where a = 11 and b = "y" and I have >no c value , > >-----Original Message----- >From: "ce" [[email protected]] >Date: 03/11/2017 10:13 AM >To: [email protected], "Rui Barradas" <[email protected]> >Subject: Re: [R] find index in a list of list > > >Exactly. Thanks a lot, I was trying sapply with to result. > >-----Original Message----- >From: "Rui Barradas" [[email protected]] >Date: 03/11/2017 10:06 AM >To: "ce" <[email protected]>, [email protected] >Subject: Re: [R] find index in a list of list > >Hello, > >Something like this? > >find <- list(a=11,b="y") >which(sapply(mylist, identical, find)) > >Hope this helps, > >Rui Barradas > > >Em 11-03-2017 14:59, ce escreveu: >> Hi all, >> >> I have a list of lists like this : >> >> mylist <- list(list(a=10,b="x"),list(a=11,b="y"),list(a=12,b="z")) >> >> I want to find the index of list in mylist where a = 11 and b = "y" >, so I want to get 2 as a result >> >> Thanks in advance >> >> ______________________________________________ >> [email protected] mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > >______________________________________________ >[email protected] mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. > >______________________________________________ >[email protected] mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
